From patchwork Wed Mar 23 15:32:52 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: andrey.konovalov@linux.dev X-Patchwork-Id: 12789842 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id EA4CEC433EF for ; Wed, 23 Mar 2022 15:33:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 78DD26B0074; Wed, 23 Mar 2022 11:33:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7176D6B0075; Wed, 23 Mar 2022 11:33:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5915E6B0078; Wed, 23 Mar 2022 11:33:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0060.hostedemail.com [216.40.44.60]) by kanga.kvack.org (Postfix) with ESMTP id 48F236B0074 for ; Wed, 23 Mar 2022 11:33:05 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 420D918286210 for ; Wed, 23 Mar 2022 15:33:04 +0000 (UTC) X-FDA: 79276044288.29.8B9557A Received: from out0.migadu.com (out0.migadu.com [94.23.1.103]) by imf12.hostedemail.com (Postfix) with ESMTP id 961D74003B for ; Wed, 23 Mar 2022 15:33:03 +0000 (UTC) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1648049582; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Mmc3nZQPUIWzZbIw9R7zdg/6fIrR3qfP7vluF20CZjk=; b=UTJfa80A9sjfbSyh7XvFmbslezbBssH3pgpUdBaLBgs3IL2A3I6NA415UycL5yEGhbwHb6 vpUhIr+s+DTQPNB7OYobvxHrvMaOkJFmdVvDpJbnJ21kD5Gc+xjflW3QFSbiifKEwW887J jc+p/iTWkpBgyYYx+H4uOeaKNyAMx8U= From: andrey.konovalov@linux.dev To: Marco Elver , Alexander Potapenko , Catalin Marinas , Will Deacon , Andrew Morton Cc: Andrey Konovalov , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, Mark Rutland , Vincenzo Frascino , Sami Tolvanen , Peter Collingbourne , Evgenii Stepanov , Florian Mayer , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH v2 1/4] stacktrace: add interface based on shadow call stack Date: Wed, 23 Mar 2022 16:32:52 +0100 Message-Id: <21e3e20ea58e242e3c82c19abbfe65b579e0e4b8.1648049113.git.andreyknvl@google.com> In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=UTJfa80A; spf=pass (imf12.hostedemail.com: domain of andrey.konovalov@linux.dev designates 94.23.1.103 as permitted sender) smtp.mailfrom=andrey.konovalov@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 961D74003B X-Stat-Signature: 8yh5fzmtg9s4cs3ayrme8b9d8un67asa X-HE-Tag: 1648049583-378539 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Andrey Konovalov Add a new interface stack_trace_save_shadow() for collecting stack traces by copying frames from the Shadow Call Stack. Collecting stack traces this way is significantly faster: boot time of a defconfig build with KASAN enabled gets descreased by ~30%. The few patches following this one add an implementation of stack_trace_save_shadow() for arm64. The implementation of the added interface is not meant to use stack_trace_consume_fn to avoid making a function call for each collected frame to further improve performance. Signed-off-by: Andrey Konovalov --- arch/Kconfig | 6 ++++++ include/linux/stacktrace.h | 15 +++++++++++++++ kernel/stacktrace.c | 21 +++++++++++++++++++++ 3 files changed, 42 insertions(+) diff --git a/arch/Kconfig b/arch/Kconfig index e12a4268c01d..207c1679c53a 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -1041,6 +1041,12 @@ config HAVE_RELIABLE_STACKTRACE arch_stack_walk_reliable() function which only returns a stack trace if it can guarantee the trace is reliable. +config HAVE_SHADOW_STACKTRACE + bool + help + If this is set, the architecture provides the arch_stack_walk_shadow() + function, which collects the stack trace from the shadow call stack. + config HAVE_ARCH_HASH bool default n diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h index 97455880ac41..b74d1e42e157 100644 --- a/include/linux/stacktrace.h +++ b/include/linux/stacktrace.h @@ -60,6 +60,9 @@ int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry, void *cookie, void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie, const struct pt_regs *regs); + +int arch_stack_walk_shadow(unsigned long *store, unsigned int size, + unsigned int skipnr); #endif /* CONFIG_ARCH_STACKWALK */ #ifdef CONFIG_STACKTRACE @@ -108,4 +111,16 @@ static inline int stack_trace_save_tsk_reliable(struct task_struct *tsk, } #endif +#if defined(CONFIG_STACKTRACE) && defined(CONFIG_HAVE_SHADOW_STACKTRACE) +int stack_trace_save_shadow(unsigned long *store, unsigned int size, + unsigned int skipnr); +#else +static inline int stack_trace_save_shadow(unsigned long *store, + unsigned int size, + unsigned int skipnr) +{ + return -ENOSYS; +} +#endif + #endif /* __LINUX_STACKTRACE_H */ diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index 9ed5ce989415..fe305861fd55 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -237,6 +237,27 @@ unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) } #endif +#ifdef CONFIG_HAVE_SHADOW_STACKTRACE +/** + * stack_trace_save_shadow - Save a stack trace based on shadow call stack + * @store: Pointer to the storage array + * @size: Size of the storage array + * @skipnr: Number of entries to skip at the start of the stack trace + * + * Return: Number of trace entries stored. + */ +int stack_trace_save_shadow(unsigned long *store, unsigned int size, + unsigned int skipnr) +{ + /* + * Do not use stack_trace_consume_fn to avoid making a function + * call for each collected frame to improve performance. + * Skip + 1 frame to skip stack_trace_save_shadow. + */ + return arch_stack_walk_shadow(store, size, skipnr + 1); +} +#endif + #else /* CONFIG_ARCH_STACKWALK */ /*